Skateboard with independent suspension and steering

ABSTRACT

A skateboard comprising a board having an independent suspension and steering assembly connecting two wheels to the board. The suspension assembly comprises a support frame rotatably coupled to an underside of the board. The steering assembly comprises a steering crank fixed to and extending from an underside of the board. The suspension assembly further comprises for each wheel: a spindle for rotatably supporting the wheel; a knuckle for holding the spindle; an upper and a lower suspension arm pivotably coupled to the support frame at an upper and at a lower point of the support frame, respectively, and also pivotably coupled to the knuckle at an upper and at a lower point of the knuckle; and a spring for resiliently holding the knuckle against the board. The steering assembly further comprises for each wheel: a tie rod coupled by a ball joint to the steering crank and to the knuckle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/IB2021/056929, filed Jul. 29, 2021, which claims priority to Portugal Patent Application No. 116615, filed Jul. 30, 2020, the contents of which are each hereby incorporated by reference in their respective entireties.

TECHNICAL FIELD

The present disclosure relates to a skateboard comprising a suspension assembly and a steering assembly for steering and connecting two parallel wheels to the board with independent suspension and steering.

BACKGROUND

Building a skateboard suspension that works independently from the steering system is especially difficult on skateboards as the skateboard turns when the user rotates it by the longitudinal or roll axis. This detail makes it impossible to use a conventional suspension as used on cars as it would result on a steering system that was affected by the suspension system. To be more specific, a system like the one used on cars would cause the wheel to rotate on the wrong axis whenever the pilot would try to steer.

Currently there are some types of solutions that try to solve this problem.

A first type of solution are skateboards that comprise an independent suspension from the turning system, having each wheel its own independent suspension with wheel travel from 30 mm to 50 mm. However this skateboards are heavy, being 3 to 4 times heavier than other skateboards as they require an independent structure that is always parallel to the ground and another that rotates as a normal skateboard does. In the cases where two structures are not built, they could not isolate the turning from the camber of the wheel.

Another disadvantage with this solution is the size, due to that the user has to use large wheels or else, with normal longboard wheels, the whole system would scratch on the ground.

An example of this suspension solution is the Bajaboard™.

Another type of solution is one that is light but has a very small wheel travel and affects the steering system. These systems are substantially cheaper but interfere with the steering, creating a much more unstable and less responsive system.

Another solution uses springs but has the spring in series with the steering system which basically is the same thing as having a stronger bushing in the traditional kingpin system. These systems will make the skate turn if just one wheel passes over a bump.

The patent document EP0933103 discloses a wheel suspension for a skateboard, fitted with four wheels or runners, having a steering linkage arm in a rotary mounting at each wheel or runner, along the line of the skateboard as a longitudinal steering member. The longitudinal steering members are linked to the superstructure by two auxiliary steering linkages for a cardanic movement action.

The patent document US2018/0185738 discloses a bifurcated truck in a laterally-sliding board wheel assembly, in which the board can easy travel forward, backwards, sideways or in any other directional combination. The wheel assembly employs a bifurcated truck system having two independent suspension arms, both operating independently from one another and from the board's castering wheels.

Prior art disclosures also have the problem of requiring further structures for example, kept always parallel to the ground which results in a much heavier skate as it requires an additional large and rigid structure.

Prior art disclosures also have the problem of the rotation of the main body (chassis) affects the camber of the wheels. Furthermore, the vertical movement of the wheel is dependent on the steering system.

Another prior art problem is that the steering system is controlled by an external device, normally a servo motor.

These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.

GENERAL DESCRIPTION

The present disclosure relates to a skateboard comprising a suspension that works independently from the steering system. In the system, multiple points are shared with the centre axis of the skateboard, resulting on a considerably different system.

The present disclosure relates to a skateboard comprising a board comprising a suspension assembly and a steering assembly for steering and connecting two parallel wheels to the board with independent suspension and steering; wherein the suspension assembly comprises a support frame rotatably coupled to an underside of the board; the steering assembly comprises a steering crank fixed to and extending from an underside of the board;

-   -   wherein the suspension assembly further comprises for each         wheel:         -   a spindle for rotatably supporting the wheel;         -   a knuckle for holding the spindle;         -   an upper and a lower suspension arm pivotably coupled to the             support frame at an upper and at a lower point of the             support frame, respectively, and also pivotably coupled to             the knuckle at an upper and at a lower point of the knuckle,             for holding the knuckle parallel to the support frame;         -   a spring for resiliently holding the knuckle against the             board;     -   wherein the steering assembly further comprises for each wheel:         -   a tie rod coupled by a ball joint to the steering crank at a             predetermined distance from the board, and coupled by a ball             joint to the knuckle, for rotating the wheel as the steering             crank rotates in respect of the support frame.

In an embodiment, the suspension assembly is a double-wishbone suspension.

In an embodiment, the upper and lower suspension arms are ‘A’-shaped arms.

In an embodiment, the spindle is rigidly mounted on the knuckle.

In an embodiment, the spring is coupled between the lower suspension arm and the board, for resiliently holding the knuckle.

In an embodiment, the spring is coupled by fastening means, particularly bolts.

In an embodiment, the knuckle comprises a knuckle shaft arranged between the pivotable coupling to the upper suspension arm and the pivotable coupling to the lower suspension arm.

In an embodiment, the knuckle shaft is pivotably coupled to the upper suspension arm and to the lower suspension arm by a resilient pivotable coupling.

In an embodiment, the resilient pivotable coupling comprises a resilient ring arranged around the knuckle shaft and within the respective suspension arm.

In an embodiment, the tie rod of each wheel is an adjustable length rod.

In an embodiment, the tie rod of each wheel comprises an inner tie rod and an outer tie rod arranged telescopically.

In an embodiment, the upper suspension arm and the lower suspension arm are arranged to remain parallel as the arms pivot.

In an embodiment, the skateboard further comprises a resilient body attached between the board and the support frame for resiliently providing resistance to the turning of the board in respect of the support frame.

In an embodiment, the body is made of an elastic polymer, in particular the elastic polymer is polyurethane.

In an embodiment, the steering assembly and the suspension assembly are made of carbon fibre or steel or aluminium.

In an embodiment, the board comprises a front part and a back part, wherein the suspension assembly and a steering assembly are located at the front part or the back part.

In an embodiment, each said front and back part comprises a suspension assembly and a steering assembly as previously described.

In an embodiment, the assemblies of the front part and assemblies of the back part are independent. Thus, being only joined by the board.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures provide preferred embodiments for illustrating the disclosure and should not be seen as limiting the scope of invention.

FIG. 1 : Schematic representation of a back view of an embodiment of the skateboard.

FIG. 2 : Schematic representation of back view of an embodiment of the skateboard when an obstacle is underneath of one wheel.

FIG. 3 : Side view representation of a lateral view of an embodiment of the skateboard.

FIG. 4 : Schematic representation of a perspective view of an embodiment of the skateboard.

FIG. 5 : Schematic representation of a front view of an embodiment of the skateboard.

FIG. 6 : Schematic representation of a perspective view of an embodiment of the skateboard.

FIG. 7 : Schematic representation of a back view of an embodiment of the skateboard.

FIG. 8 : Schematic representation of a perspective view of an embodiment of the skateboard.

FIG. 9 : Schematic representation of a steering assembly of an embodiment of the skateboard.

FIG. 10 : Schematic representation of a steering assembly of an embodiment of the skateboard when is turning.

FIG. 11 : Schematic representation of a suspension assembly of the skateboard.

FIG. 12 : Schematic representation of a suspension assembly of the skateboard when an obstacle is underneath a wheel.

FIG. 13 : Schematic representation of a suspension mechanism of an embodiment of the skateboard.

FIG. 14 : Schematic representation of the steering mechanism of an embodiment of the skateboard.

DETAILED DESCRIPTION

The present disclosure relates to a skateboard comprising a board 2 comprising a suspension assembly and a steering assembly for steering and connecting two parallel wheels 3 to the board with independent suspension and steering; wherein the suspension assembly comprises a support frame 8 rotatably coupled to an underside of the board; the steering assembly comprises a steering crank 12 fixed to and extending from an underside of the board;

-   -   wherein the suspension assembly further comprises for each         wheel:         -   a spindle 13 for rotatably supporting the wheel;         -   a knuckle 9 for holding the spindle;         -   an upper 7 a and a lower suspension arm 7 b pivotably             coupled to the support frame at an upper and at a lower             point of the support frame, respectively, and also pivotably             coupled to the knuckle at an upper and at a lower point of             the knuckle, for holding the knuckle parallel to the support             frame;         -   a spring 5 for resiliently holding the knuckle against the             board;     -   wherein the steering assembly further comprises for each wheel:         -   a tie rod 4 coupled by a ball joint to the steering crank at             a predetermined distance from the board, and coupled by a             ball joint to the knuckle, for rotating the wheel as the             steering crank rotates in respect of the support frame.

FIG. 1 shows a schematic representation of a back view of an embodiment of a skateboard 1 where: 2 represents a board, 3 represents two parallel wheels, 4 represents a tie rod, 5 represents a spring, 6 represents a spring bolt, 7 a represents an upper suspension arm and 7 b represents a lower suspension arm and 14 represents a body.

FIG. 2 shows a schematic representation of the back view of an embodiment of a skateboard 1 when an obstacle appears, like a bump or a rock for example, on the right side where: 2 represents a board, 3 represents two parallel wheels, 4 a represents an inner tie rod, 4 b represents an outer tie rod, 5 represents a spring, 6 represents a spring bolt, 7 a represents an upper suspension arm, 7 b represents a lower suspension arm, 9 represents the knuckle and 14 a body. It is shown that the suspension does not affect the steering system. The left and right wheel are at different heights but the wheels are not turning.

FIG. 3 shows a side view representation of a lateral view of an embodiment of a skateboard 1 where: 3 two parallel wheels, 4 represents a tie rod right, 5 represents a spring.

FIG. 4 shows a side view representation of a perspective view an embodiment of a skateboard 1 where: 4 a represents an inner rod, 4 b represents an outer tie rod, 5 represents a spring, 16 represents a first ball joint, 10 represents a second ball joint 7 represents a suspension arm.

In an embodiment, the board comprises a front side and a backside where in the front side of the board, the suspension assembly for each of the two parallel wheels 3 comprises one spring and in the backside, the suspension assembly for each of the two parallel wheels 3 also comprises one spring.

In an embodiment the spring 5 are coupled to the board 2.

FIG. 5 shows a front view of an embodiment of a skateboard 1 where: 4 a represents an inner tie rods 4 b represents an outer tie rod, 7 b represents a lower suspension arm, 16 represents a first ball joint, 10 represents a second ball joint, 11 represents a tie rod socket.

FIG. 6 shows a perspective view of an embodiment of a skateboard 1 where: 4 represents a tie rods and 7 b represents a lower suspension arm and 7 a represents an upper suspension arm.

FIG. 7 shows a back-view representation of an embodiment of a skateboard 1 when the skateboard is turning. It can be seen that the board is leaned to the right side.

FIG. 8 shows a perspective view of an embodiment of a skateboard 1 when the skateboard is turning where 8 is a support frame, 13 is a spindle. The spindle is responsible to rotatably support the wheel.

FIG. 9 shows a representation of a steering mechanism of a skateboard where: 2 represents a board, 3 represents two parallel wheels, 4 represents a tie rod, 9 represents a knuckle, 16 represents the first ball joint, 10 represents the second ball joint and 12 represents the steering crank.

FIG. 10 shows a representation of a steering mechanism of a skateboard where: 2 represents a board, 4 represents a tie rod, 9 represents a knuckle for the wheel, 12 represents the steering crank and 13 is the spindle. It is shown that when the wheel 3 is rotating the steering crank 12 rotates in respect of the support frame.

FIG. 11 shows a schematic representation of a suspension mechanism of a skateboard where: 2 represents the board, 3 represents a wheel, 7 a represents the upper suspension arms, 7 b represents a lower suspension arm, 8 represents a support frame, 9 represents a knuckle and 13 a spindle.

FIG. 12 shows a schematic representation of a suspension mechanism of a skateboard where: 2 represents the board, 3 represents a wheel, 7 a represents an upper suspension arms, 8 represents a support frame, 9 represents a knuckle and 12 represents an obstacle. This figure shows that when an obstacle 15 appears, the user will lean the board sideway 2 for the wheel 3 to pass over said object, and the respective upper 7 a and lower 7 b arms of the suspension of the side where the obstacle is will go up, keeping the knuckle parallel to the support frame.

FIG. 13 shows a schematic representation of the suspension mechanism where, despite rotation of the board in respect of the support frame, the suspension structure is not altered.

FIG. 14 shows a schematic representation of the steering mechanism, where, despite suspension movement of a wheel caused by an obstacle 15, the steering structure is not altered (i.e. there is no wheel turning).

In an embodiment, the suspension assembly and the steering assembly are independent. These embodiments show that the suspension assembly does not influence the steering assembly since they are completely independent of each other.

In an embodiment, the centre of rotation of the whole assembly is concentrated on the centre of the board. Surprisingly, this way it is possible to pass over bumps without affecting the steering assembly and the camber and it is possible to turn without affecting the camber or the suspension assembly.

In an embodiment, the bolt joint may comprise an elastic polymer. The polymer is polyurethane.

In an embodiment, the support frame 8 is rotatably coupled and is always perpendicular to the wheel, even when the wheel is moving upwards and the board is tilted.

In an embodiment, the second ball joint 10 and tie rod socket 11 moves upwards and downwards.

In an embodiment, the springs of the suspension assembly of each wheel cancel each other when turning/pivoting the board, not offering resistance while turning. This happens because both of them have preload and while turning, one of the springs gets compressed and the other extends, so one helps the other. Although the spring getting extended has less energy stored and the spring being compressed is increasing the stored energy, the resulting force is balanced due to the change in the angle of the springs during the movement. The change in the angle changes the ratio wheel/spring travel that is why it balances the force. This way the springs of two lateral wheels only offer resistance for the suspension assembly and cancel each other for the turning/steering assembly.

In an embodiment, the steering assembly and the suspension assembly are smaller, lighter and allows the use of normal skateboards wheels. While comparing to the other kind of simpler systems it has basically the same weight of a normal longboard truck while giving a full suspension system with a real wheel travel of 46 mm.

The term “comprising” whenever used in this document is intended to indicate the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The above described embodiments are combinable.

The following claims further set out particular embodiments of the disclosure. 

1. A skateboard, comprising: a board comprising a suspension assembly and a steering assembly connecting two parallel wheels to the board with independent suspension and steering; wherein the suspension assembly comprises a support frame rotatably coupled to an underside of the board; wherein the steering assembly comprises a steering crank fixed to and extending from an underside of the board; wherein the suspension assembly further comprises for each wheel: a spindle rotatably supporting the wheel; a knuckle holding the spindle; an upper and a lower suspension arm pivotably coupled to the support frame at an upper and at a lower point of the support frame, respectively, and also pivotably coupled to the knuckle at an upper and at a lower point of the knuckle, whereby the knuckle is held parallel to the support frame; a spring resiliently holding the knuckle against the board; wherein the steering assembly further comprises for each wheel: a tie rod coupled by a first ball joint to the steering crank at a predetermined distance from the board and coupled by a second ball joint to the knuckle, wherein the wheel rotates as the steering crank rotates in respect of the support frame.
 2. The skateboard according to claim 1, wherein the suspension assembly is a double-wishbone suspension.
 3. The skateboard according to claim 1, wherein the upper and lower suspension arms are ‘A’-shaped arms.
 4. The skateboard according to claim 1, wherein the spindle is rigidly mounted on the knuckle.
 5. The skateboard according to claim 1, wherein the spring is coupled between the lower suspension arm and the board, for resiliently holding the knuckle.
 6. The skateboard according to claim 1, wherein the spring is coupled by fastening means.
 7. The skateboard according to claim 1, wherein the knuckle comprises a knuckle shaft arranged between the pivotable coupling to the upper suspension arm and the pivotable coupling to the lower suspension arm.
 8. The skateboard according to claim 7, wherein the knuckle shaft is pivotably coupled to the upper suspension arm and to the lower suspension arm by a resilient pivotable coupling.
 9. The skateboard according to claim 8, wherein the resilient pivotable coupling comprises a resilient ring arranged around the knuckle shaft and within the respective suspension arm.
 10. The skateboard according to claim 1, wherein the tie rod of each wheel is an adjustable length rod.
 11. The skateboard according to claim 10, wherein the tie rod of each wheel comprises an inner tie rod and an outer tie rod arranged telescopically.
 12. The skateboard according to claim 1, wherein the upper suspension arm and the lower suspension arm are arranged to remain parallel as the arms pivot.
 13. The skateboard according to claim 1, further comprises a resilient body attached between the board and the support frame thereby providing resilient resistance to the turning of the board in respect of the support frame.
 14. The skateboard according to claim 1, wherein the body is made of an elastic polymer, in particular the elastic polymer is polyurethane.
 15. The skateboard according to claim 1, wherein the steering assembly and the suspension assembly are made of carbon fiber or steel or aluminium.
 16. The skateboard according to claim 1, wherein the board comprises a front part and a back part, and wherein the suspension assembly and a steering assembly are located at the front part or the back part.
 17. The skateboard according to claim 16, wherein each said front and back part comprises a suspension assembly and a steering assembly.
 18. The skateboard according to claim 17, wherein the suspension and steering assemblies of the front part and suspension and steering assemblies of the back part are independent. 